Human tissue is sensitive for different types of radiation. The radiation which may consist of energy bins may affect cell structures when it hits the human body. Ionizing radiation, for example, can change the structure of the cells, sometimes creating potentially harmful effects that are more likely to cause changes in tissue. These changes can interfere with cellular processes so cells might not be able to divide or they might divide too much, resulting in cancer.
Radiation dose meters are common for use in industries, hospitals, dentist sites, etc. in which the presence of and exposure to low levels of radiation is a hazard and must be monitored. In a hospital or at dentist, for example, patients, physicians and nurses may also encounter situations in which they may risk exposure to radiation and require a means of monitoring such exposure.
The radiation dose meters of today normally provide a direct value in a predetermined unit. However, to present measured values in this way normally is not easy to be understood by none-expert users and to be interpret to a relevant radiation dose situation and consequently unclear for the user how to avoid unnecessary exposure to radiation, which may increase health hazard.
Authorities have specified some radiation dose limits, which should not be exceeded for individuals/groups of people, to reasonably limit humans' health risks for radiation.
U.S. Pat. No. 4,642,463 relates to a radiation monitor, which includes a radiation detector, a digital processor and a display. The digital processor is responsive to externally input information corresponding to alarm radiation rate, alarm radiation dose and alarm time-to-go. The digital processor integrates the perceived real time radiation rate to produce total dose information. The processor can then compare total dose information to alarm dose, compare sensed radiation rates to alarm rate and compute time-to-go, by dividing the difference between alarm dose and total dose by the present radiation rate, and finally comparing computed time-to-go to alarm time to go. The processor initiates an alarm condition for altering the user of sensed radiation rate exceeds alarm radiation rate, if total dose information exceeds alarm dose information or if time-to-go, as computed, is less than alarm time-to-go information. Additional functions performed include determination of expected dose, first opportunity computations and decay time-to-go computations. In all these computations the processor is capable of extrapolating predicted radiation rates. Thus, this document describes a technique using accumulated dose while the present invention uses continues running mean value and radiation intensity. There is also a difference in when and how a warning is provided. While the present invention provides a warning for whether the radiation at the current time is safe or not, this document provides information on how long it is left before the radiation is unsafe.
U.S. Pat. No. 7,592,603 relates to a radiation detector performing both rate and dose measurements for personal safety and also to provide measurements that are sufficiently sensitive for security applications. In one embodiment, a radiation detector has a first measurement channel and a second measurement channel, where the second measurement channel can measure radiation at levels that would saturate the first measurement channel.